The Internet Assigned Numbers Authority is in head of assigning internet protocol numbers. They provide an up-to-date file containing all assigned internet protocols, ftp.iana.org/assignments/protocol-numbers. Most Unix systems need those data in a file called /etc/protocols. iana2protocols converts the file provided by the IANA to a file suitable for Unix systems.
$ ftp ftp://ftp.iana.org/assignments/protocol-numbers $ iana2protocols < protocol-numbers > /etc/protocols
$ diet -Os gcc -Wall -s -nostdinc -o iana2protocols iana2protocols.c || \ gcc -Wall -Os -s -o iana2protocols iana2protocols.c